OK, I've read all the info on this site and many others. The engine in my 5700 has a casting number on it --3738307 and the code above the starter seems to be 00N4. I thought the first one was supposed to be A-L ? Spare engine is 3835911 and 00N3. Blocks look different from each other, but both have 4 screws on valve covers and low water pumps. I put alternator bracket kit on the first engine and had to space out the mount because it hit another boss in the block below it. The other engine uses a bracket the bolts to the block just above the oilpan mount. Help Mr. Wizards !!! What do I have?
